According to the U.S. Fish and Wildlife Service, the last time the winged mapleleaf mussel was seen in the Duck was more than 20 years ago.

The mussel historically had a range from Minnesota to Arkansas, but today there are only five known populations.

Last week, federal and state biologists placed 103 juvenile mussels back in the Duck River.

The 2-year-old mussels were propagated at Missouri State University.

The Duck River was selected as a reintroduction site, in part, because it already has a diverse mussel population.

And Tennessee already has long-term monitoring sites on the Duck that will track the winged mapleleaf mussels’ progress. Biologists laser engraved numbers on the mussels to help identify them for study.